
 The CO high-velocity jet consists of two components: a central component of diameter \(\le 400\)  au associated with high-velocity molecular knots (also detected in SO) and a surrounding gas layer accelerated on a length scale \(\delta _0\approx \)  700 au, whose diameter gradually increases up to several 1000 au at about 2000 au from the protostar.

 Along the main jet axis, the CO gas velocity can be simply fitted as a function of distance \(\delta \)  to the protostar by the relation \((V_r-V_{lsr})/V_0\) = \(\exp (-\delta _0/\delta )\) 
where \(V_{lsr}\) = \(-10.9\hbox{\hspace{1.99997pt}km\hspace{1.99997pt}s$^{-1}$}\)  is the ambient cloud velocity, \(V_0\)  is the terminal velocity in the jet lobe relative to the source \(\approx +75\hbox{\hspace{1.99997pt}km\hspace{1.99997pt}s$^{-1}$}\)  (\(-118\hbox{\hspace{1.99997pt}km\hspace{1.99997pt}s$^{-1}$}\) ) and \(\delta _0\)  is the length scale \(\approx 700\)  au (600 au) in the northern (southern) hemisphere.
Analysis of the CO Position-Velocity diagrams shows that the jet layer consists of quiescent protostellar material entrained by extremely-high velocity knots. The material entrainment appears to be more efficient in the northern than in the southern lobe.

 The jet molecular gas emission reveals the presence of 18 bright knots in either lobes of the jet with a dynamical timescale of \(55\hbox{\hspace{1.99997pt}yr}\)  between subsequent ejections close (\(< 1000\)  au) to the protostar. The knots have a typical size of 2, with a tendency to increase with distance to the protostar. We have identified knots NB and HH377 as the terminal bowshocks of the northern and southern lobes, respectively.

 Assuming a standard CO abundance of \(10^{-4}\)  relative to \(\hbox{H${}_2$}\) , a simple radiative transfer analysis in the LVG approximation with MadeX yields a typical mass of \(10^{-3}\hbox{\hspace{1.99997pt}$M_\odot $}\)  for the bullets. SO observations at \(0.4\)  show that the knots leave the inner protostellar regions (\(\sim 200\)  au) at high-velocity, with marked velocity fluctuations between subsequent ejections. The cumulative knot mass function allows to estimate mass-loss rates of \(2.7\times 10^{-5}\hbox{\hspace{1.99997pt}$M_\odot $}\hbox{\hspace{1.99997pt}yr$^{-1}$}\)  and \(8.9\times 10^{-6}\hbox{\hspace{1.99997pt}$M_\odot $}\hbox{\hspace{1.99997pt}yr$^{-1}$}\)  in the northern and southern lobes, respectively. The jet mass-loss rates appear steady with time. The higher mass-loss rate value in the North is consistent with protostellar material entrainment by the jet.

  The knot interval distribution between subsequent knots is approximately bi-modal with intervals of \(\sim 55\)  yr and \(\sim 150\)  at short (\(< 12\) ) and large (\(> 12\) ) distance from the protostar, respectively. In the northern jet, the velocity fluctuations are large enough (\(\sim 15\hbox{\hspace{1.99997pt}km\hspace{1.99997pt}s$^{-1}$}\) ) that the spatial separation between knots can be overcome in a dynamical timescale of \(\simeq 500\hbox{\hspace{1.99997pt}yr}\) , when knots will have travelled a typical distance of 12 (\(10^4\)  au) from the protostar. This naturally explains lack of knots at large distances from the source. This result is also supported by the higher masses found for the knots at larger distances.

Analysis of the knot spatial distribution suggests precession as origin of the wiggling structure of the outflow. Applying the Masciadri-Raga formalism, we obtain an accurate description of the jet morphology, taking into account the outflow inclination angle with respect to the plane of the sky. The same model allows us to discard binary orbital motions as the source of the Cep E-mm jet wiggling, since it would require protostellar masses too large to be reconciled with the source luminosity and mass. We propose that jet precession takes its origin in tidal perturbations of the associated protostellar disk by a binary companion, yet to be identified, in agreement with previous work by [1]}.

